@0xc0787ef6e3cb87e1;

using CSharp = import "programming_language/csharp.capnp";
$CSharp.namespace("FabAccessAPI.Schema");

using import "state.capnp".State;
using import "state.capnp".Update;

interface Notifyable {
    state @0 () -> ( state :State );
    # Returns the current state of a resource.

    subscribe @1 ( subscriber :Subscriber ) -> ( subscription :Subscription );
    # Subscribe to state updates. The passed in `subscriber` is an interface implemented on the
    # client side that a server calls to send update notifications.
}

interface Subscriber {
    update @0 ( update :Update ) -> ();
    # Called by a server when a new state was produced for this resource.  This method MAY not be
    # called when a resource was updated but did not change its state.  A server will only ever have
    # one running update call per client session, so a client can limit the rate of updates by not
    # resolving this call immediately.  A server will coalesce multiple updates into a single update
    # notification, meaning a client is not guaranteed to receive every intermediary state for a
    # resource.
}

interface Subscription { }